1911.] Serum Reactions in Pulmonary Tuberculosis. 377 



specific adsorption of complement by the antigen dilution, the more marked 

 will be the amount of apparent complement fixation by suitable sera. For 

 the demonstration of both the inbibitive and fixation reactions considerably 

 more than one unit of available complement should be present to show the 

 specific action of the serum. For use the stock solution is freshly diluted 

 with saline. This gives a cloudy emulsion. The opacity of the different 

 preparations has not always borne a proportionate relation to the anti- 

 complementary effects. 



Employing as already mentioned two units of both complement and 

 hemolysin the full anti-complementary effect with saline takes place in the 

 neighbourhood of a 1/10 to 1/20 dilution. With the determination of 

 this point four dilutions* have been used in the following proportions, 

 namely, 1 c.c, 0-5 c.c, - 25 c.c, and 01— - 05 c.c. "With these strengths, 

 which I will call for convenience respectively the first, second, third, and 

 fourth dilutions, the antigen and complement controls to any protocol should 

 result about as follows : — 



Table I. 





Freshly diluted 

 antigen. 



Saline solution. 



Complement. 



End results in terms 

 of haemolysis. 



2 

 3 

 4 

 5 

 6 

 . 7 

 8 



0-5 „ 

 -25 „ 



o-i „ 

 o-i „ 



Saline 



1 -0 c.c. 



(2 units) 1 -0 c.c. 

 (2 „ ) „ 

 (2 „ ) „ 

 (2 „ ) „ 

 (1 unit) "5 c.c. 

 (2 units) 1 -0 „ 

 (1 unit) 0-5 „ 

 (i „ ) -25 „ 



' None. 

 Some (± ?). 

 Complete. 



Some (± ?). 

 Complete. 



Some (± ?). 



Complement is standardised before each protocol, and an amount already 

 defined as a two -unit strength employed. The three controls (Table I) for 

 this are added to each protocol to show the amount of fixative available at 

 the time and under the conditions of the protocol. Considerable variation 

 may take place in a short space of time, so that this has been found 

 advantageous for a satisfactory comparison of different protocols. As each 

 addition is brought to a full unit in all protocols, the effects of the saline 

 dilution are closely related. With alteration of the fixative strength of 



* Sachs and Rondoni-Florenz ('Zeits. f. Immunitats-forschung,' 1909, 1, Abt. 132) call 

 attention to the fact that fractional dilution " often results in a very increased intensity 

 of the reaction." This has in ray hands produced marked changes in the antigen controls, 

 and consequently, one may assume, may play a considerable rSle in the antigen serum 

 tubes. Particularly with the stronger dilutions fractionally made, one can observe that 

 the upper part carries the greater part of the antigen. 



